[AERODYNAMICS]All the above is to say that using the spoilers on approach isn't entirely unsafe, and in order to turn, they are actually part of standard procedure. To me, use of spoilers usually means either ATC gave a late descent, or ATC gave pilot's discretion and lack of proper descent planning lead to a high approach.

Whilst what you say is true aka VC10 which I believe was the first to introduce the idea of using speed brakes to assist the turn. Remember that in this case they are linked to the FD or other control so that when the pilot or AP move the control column to a certain degree "and at a certain airspeed" the speed brakes on one wing raise slightly to assist.The thread here though is speaking about using them to slow down i.e. to their full capacity during approach and that is very very risky in real life. Certainly they are to be used to bring the speed down to that required for holding or arriving and departing a STAR to get down quickly in order to capture the localiser if one is too high. (Used frequently at limf and lipz) But on final approach down the ILS they should not be used at all!!vololiberista

Whilst what you say is true aka VC10 which I believe was the first to introduce the idea of using speed brakes to assist the turn. Remember that in this case they are linked to the FD or other control so that when the pilot or AP move the control column to a certain degree "and at a certain airspeed" the speed brakes on one wing raise slightly to assist.The thread here though is speaking about using them to slow down i.e. to their full capacity during approach and that is very very risky in real life. Certainly they are to be used to bring the speed down to that required for holding or arriving and departing a STAR to get down quickly in order to capture the localiser if one is too high. (Used frequently at limf and lipz) But on final approach down the ILS they should not be used at all!!vololiberista

My point of bringing in the reference to spoilerons wasn't to describe perfectly how they operate (if you want to get into that discussion, I can create a separate thread about it, but that's not the issue here), rather, how they relate to the topic at hand. Mostly, I added that argument in there to point out that if activation of spoilers is inherently unsafe with the use of flaps, they would not be used as a roll-assisting device in that phase. The speedbrakes to which you refer are better described by what you see on the tail of Avros or Fokkers. They have no other purpose than that of slowing the aircraft down. I know I'm parsing words here, but doing so is important to understand the difference in how they operate and how they affect the aircraft.I know there has been mention in this thread of using spoilers to slow the aircraft down, but I have already explained how spoilers achieve this goal:

[AERODYNAMICS]While the above is mostly true, I'd argue that the use of speedbrakes doesn't essentially turn your aircraft into a brick. The wings are still there, and still primarily functional at that. The only thing that is happening is that the wings are producing less lift. A more appropriate name for them would be the alternate 'spoilers' term. All they are doing is spoiling the lift. Because of that, for the same angle of attack, a descent will be at a higher rate without an increase in airspeed (because of the lost lift); or, for the same descent rate, a higher angle of attack will be necessary, which increases the deceleration rate.[...][/AERODYNAMICS]

Speedbrakes are meant to increase drag with little/no change in lift.Spoilers are meant to spill lift, and as a result, increase drag.In the case of the MD-11, the control surface we are addressing is meant to spill (spoil) lift, and as a result increase drag. Understanding the distinct differences between the two may help people fly the aircraft more precisely.To be even more clear:If you hold the nose at an attitude that results in level/unaccelerated flight, and then deploy spoilers, while maintaining the same attitude and power settings, you will not necessarily decelerate (or you may initially but briefly), rather, you will begin to descend at the speed you were earlier flying in level/unaccelerated flight.If anyone hasn't already, you should all read this, if you're at all interested in flying. It will further explain and support my points:Stick and Rudder

All the more reason why the originator of the thread should not use them on approach!vololiberista

Yet glider pilots, depending on the approach, will use them until touchdown...They are not inherently dangerous. If you're high on the approach, I see no reason that you should not use them.If you are very high, however, the MD-11 has proven at least three times that you should go around. If you do not fly a stable approach, it'll bite back near touchdown.

Yet glider pilots, depending on the approach, will use them until touchdown...They are not inherently dangerous. If you're high on the approach, I see no reason that you should not use them.If you are very high, however, the MD-11 has proven at least three times that you should go around. If you do not fly a stable approach, it'll bite back near touchdown.

Remember that glider pilots are flying much slower and are flying a/c with a completely different configuration!!Just fly the approach properly and you won't need to use them.vololiberista

@vololiberistaScandinavian13 is spot on. I couldn't say it better. In the air they are called speedbrakes, while landing spoilers. When you look at the MD11 and use full speedbrake (in the air) and compare it to ground spoilers (on nose down while landing), you'll see the difference in % that they are up. With the 737 you can even see it better.Something else too lose speed is making a S turn if you have still enough miles to go and possible with ATC. Another trick (specially with the 737) is use the speedbrakes as long as possible and (even above the gilde) reduce as fast as you can (low or no -VS) and select everything for landing. On target speed spd brakes down and arm them. You will see that you will maintain apr spd but you can descent quicker. Also depending on mls out ofcourse! If you are established at 1000 ft continue the approach, if not, GA.Reg,John

@vololiberistaScandinavian13 is spot on. I couldn't say it better. In the air they are called speedbrakes, while landing spoilers. When you look at the MD11 and use full speedbrake (in the air) and compare it to ground spoilers (on nose down while landing), you'll see the difference in % that they are up. With the 737 you can even see it better.Reg,John

not so!!!! They are called either speed brakes or Spoilers!! Check the VC10 that has only spoilers. Used in the air both for assisting turns at low speed below 250 ias, dumping lift in order to descend quickly, losing airspeed whilst maintaining level flight and finally to dump lift on touch down. For whatever reason they are used for, a good pilot will not need to nor never use them on final approach!vololiberista

Whatever you want to call them, if you need them on final you screwed up long before the approach started.

@ vololiberista The VC10 is an aircraft somewere from the 60's. Maybe the RAF is the only one still flying them (as tanker I believe). You could be right that they do both. I don't know. It sounds strange to me though, because if you want a lower speed then it's not very handy too lose altitude faster because then youre speed will increase too and if you want to lose altitude you still have VS or manual with your yoke.Anyway, on modern aircraft it is as subscribed before and also those parts from the airbrakes/spoilers are used for (inboard) ailerons. Trust me.@BSWCompletely right! I was talking about hot and high.John